Studies on the anion sensitivity of immobilized metalloporphyrins for application as optochemical sensors

Different metal complexes of tetra(4-aminophenyl)porphyrin and tetra(4-N-methylpyridyl) porphyrin have been immobilized in thin films of Nafion. The absorbance spectra of the immobilized metalloporphyrins are found to change while coordinating anions such as iodide and thiocyanate and an organic nucleophile like pyridine. To study the potential of these layers for application as optochemical sensors, the properties of the reaction have been investigated. The immobilized cobalt complex is found to be able to determine thiocyanate reversibly. No loss of reagent is found over four weeks under continuous operation.